在系统相机中拍照，获取照片文件的路径。代码实现，通用简介

获取照片文件的路径可以通过以下步骤实现：

1. 获取相机对象

Camera camera = Camera.open();

2. 创建相机回调函数

private Camera.PictureCallback mPicture = new Camera.PictureCallback() {
    @Override
    public void onPictureTaken(byte[] data, Camera camera) {
        // 处理照片数据
    }
};

3. 开始预览相机

SurfaceView surfaceView = findViewById(R.id.surfaceView);
SurfaceHolder holder = surfaceView.getHolder();
holder.addCallback(new SurfaceHolder.Callback() {
    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        try {
            camera.setPreviewDisplay(holder);
            camera.startPreview();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {

    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {

    }
});

4. 拍照并获取照片文件路径

camera.takePicture(null, null, mPicture);

在 `onPictureTaken` 回调函数中，可以将照片数据写入文件，并获取照片文件的路径。例如：

File pictureFile = getOutputMediaFile();
if (pictureFile == null) {
    Log.d(TAG, "Error creating media file, check storage permissions");
    return;
}

try {
    FileOutputStream fos = new FileOutputStream(pictureFile);
    fos.write(data);
    fos.close();
    Log.d(TAG, "Picture saved: " + pictureFile.getAbsolutePath());
} catch (FileNotFoundException e) {
    Log.d(TAG, "File not found: " + e.getMessage());
} catch (IOException e) {
    Log.d(TAG, "Error accessing file: " + e.getMessage());
}

`getOutputMediaFile` 方法用于创建照片文件并返回文件对象。例如：

private static File getOutputMediaFile() {
    File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
            Environment.DIRECTORY_PICTURES), "MyCameraApp");

    if (!mediaStorageDir.exists()) {
        if (!mediaStorageDir.mkdirs()) {
            return null;
        }
    }

    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
    File mediaFile = new File(mediaStorageDir.getPath() + File.separator +
            "IMG_" + timeStamp + ".jpg");

    return mediaFile;
}

注意需要添加相应的权限，例如相机权限和读写存储权限。